Crowbcat created a Portal setup that had Chell, the game’s heroine, trapped between two portals that crushed her. The results were an astounding wonderland of psychedelic visuals
From Cory Doctorow on BoingBoing, who adds:
I don’t know what would be cooler: if this were an emergent property of the game’s programming, or if the designers hid it in the code and waited for an adventurous sort to discover it.
I know that in Portal when a surface with a portal on it moves, the portal is usually removed, so I was suspicious of this. But apparently:
For the record: Portals can move. In Chapter 5 (The Escape) at the thirty-third level of the game, you have to place portals onto moving panels to cut neurotoxin generator tubes by using a laser. This gameplay mechanism is not activated by default, so a special command was used to achieve the experiment.